| Topic: |
Science > Physics |
| User: |
"kenseto" |
| Date: |
22 Aug 2006 10:16:57 AM |
| Object: |
Questions on world-line |
In SR the world line is the path of an object in space with the passage of
time. Each object has its own world-line.
Questions:
1. Does this mean that the world-line of an object is the result of the
individual motion of the object?
2. SR says that there is no such thing as individual motion. There is only
relative motion then how does an individual object have world-line?
Ken Seto
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| User: "Dirk Van de moortel" |
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| Title: Re: Questions on world-line |
22 Aug 2006 11:56:54 AM |
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"kenseto" <kenseto@erinet.com> wrote in message news:JdFGg.64268$vl5.40512@tornado.ohiordc.rr.com...
In SR the world line is the path of an object in space with the passage of
time. Each object has its own world-line.
Questions:
1. Does this mean that the world-line of an object is the result of the
individual motion of the object?
2. SR says that there is no such thing as individual motion. There is only
relative motion then how does an individual object have world-line?
A worldline is not at all specific to SR.
When you have a coordinate system (including a clock), and when you
know the spatial coordinates - for example ( x(t), y(t), z(t) ) - of the point
of an object (or a point object, or a particle) as a function of time, then
you can "draw" the set of events that shows the history and future of
the object in a diagram that includes time on an equal footing as (perhaps
a subset of) the spatial axes.
This way, the set of points (events actually) defines a line in the diagram.
That line is a worldline. For a given point object each coordinate
system has a different worldline.
An alternative way (more abstract and perhaps preferable) is to define
the worldline of an object as the set of all its events, independently of
any coordinate system. In that case the point object has a unique
worldline that is described by different equations in different coordinate
systems.
Dirk Vdm
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| User: "Sorcerer" |
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| Title: Re: Questions on world-line |
22 Aug 2006 12:31:04 PM |
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"Dirk Van de moortel" <dirkvandemoortel@ThankS-NO-SperM.hotmail.com> wrote
in message news:qHGGg.35352$tc4.487567@phobos.telenet-ops.be...
[anip]
xi, x'?
Androcles
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| User: "Timo A. Nieminen" |
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| Title: Re: Questions on world-line |
22 Aug 2006 02:51:28 PM |
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On Tue, 22 Aug 2006, kenseto wrote:
In SR the world line is the path of an object in space with the passage of
time. Each object has its own world-line.
Questions:
1. Does this mean that the world-line of an object is the result of the
individual motion of the object?
2. SR says that there is no such thing as individual motion. There is only
relative motion then how does an individual object have world-line?
Consider an object, with position in a particular inertial coordinate
system (aka inertial reference frame) given by r(t). It can only be in one
place at a time, and is always somewhere at any time; thus r(t) is a
function. The problem is that not only does r depend on choice of
coordinate system, but so does t.
So, what to do? Introduce a parameter that is independent of choice of
coordinate system, such as the "proper time" T, and we can write
R(T) = (r,t)
as a 4-vector valued function. How can any individual object _not_ have a
world line?
Consider two points in space, A and B. Consider a displacement vector from
A to B. This only depends on the relative positions of A and B. However,
the (x,y,z) we might choose to represent the vector with very much depend
on our choice of coordinate system.
Likewise, R(T1) - R(T2) only depends on the relative 4-positions of the
two events. The (x,y,z,t) depend on the chosen coordinate system. Relative
motion of the object and the origin of the chosen coordinate system
affects the (x,y,z,t) description of the world line, but can't affect the
geometry of the world line.
How is this different between SR and Galileian relativity? In Galileian
relativity, transformations of time are separate from transformations of
the spatial coordinates, leaving only translations, reflections, and
changes of scale in t. Still, the same basic principles hold. Surely, in
a theory (perhaps something called IRT that has been posted on this ng)
that is a covering theory of SR, in the same way that SR is a covering
theory of Galileian relativity, this would be the same?
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html
.
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| User: "kenseto" |
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| Title: Re: Questions on world-line |
23 Aug 2006 08:01:26 AM |
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"Timo A. Nieminen" <timo@physics.uq.edu.au> wrote in message
news:Pine.WNT.4.64.0608230531570.1380@serene.st...
On Tue, 22 Aug 2006, kenseto wrote:
In SR the world line is the path of an object in space with the passage
of
time. Each object has its own world-line.
Questions:
1. Does this mean that the world-line of an object is the result of the
individual motion of the object?
2. SR says that there is no such thing as individual motion. There is
only
relative motion then how does an individual object have world-line?
Consider an object, with position in a particular inertial coordinate
system (aka inertial reference frame) given by r(t). It can only be in one
place at a time, and is always somewhere at any time; thus r(t) is a
function. The problem is that not only does r depend on choice of
coordinate system, but so does t.
So, what to do? Introduce a parameter that is independent of choice of
coordinate system, such as the "proper time" T, and we can write
R(T) = (r,t)
as a 4-vector valued function. How can any individual object _not_ have a
world line?
Consider two points in space, A and B. Consider a displacement vector from
A to B. This only depends on the relative positions of A and B. However,
the (x,y,z) we might choose to represent the vector with very much depend
on our choice of coordinate system.
Likewise, R(T1) - R(T2) only depends on the relative 4-positions of the
two events. The (x,y,z,t) depend on the chosen coordinate system. Relative
motion of the object and the origin of the chosen coordinate system
affects the (x,y,z,t) description of the world line, but can't affect the
geometry of the world line.
You did not answer my question: What is the motion of an object that cause
it to have a world-line???
Ken Seto
How is this different between SR and Galileian relativity? In Galileian
relativity, transformations of time are separate from transformations of
the spatial coordinates, leaving only translations, reflections, and
changes of scale in t. Still, the same basic principles hold. Surely, in
a theory (perhaps something called IRT that has been posted on this ng)
that is a covering theory of SR, in the same way that SR is a covering
theory of Galileian relativity, this would be the same?
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html
.
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| User: "Timo A. Nieminen" |
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| Title: Re: Questions on world-line |
24 Aug 2006 01:27:54 PM |
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On Wed, 23 Aug 2006, kenseto wrote:
"Timo A. Nieminen" <timo@physics.uq.edu.au> wrote:
On Tue, 22 Aug 2006, kenseto wrote:
In SR the world line is the path of an object in space with the passage
of
time. Each object has its own world-line.
Questions:
1. Does this mean that the world-line of an object is the result of the
individual motion of the object?
2. SR says that there is no such thing as individual motion. There is
only
relative motion then how does an individual object have world-line?
Consider an object, with position in a particular inertial coordinate
system (aka inertial reference frame) given by r(t). It can only be in one
place at a time, and is always somewhere at any time; thus r(t) is a
function. The problem is that not only does r depend on choice of
coordinate system, but so does t.
So, what to do? Introduce a parameter that is independent of choice of
coordinate system, such as the "proper time" T, and we can write
R(T) = (r,t)
as a 4-vector valued function. How can any individual object _not_ have a
world line?
[cut]
You did not answer my question: What is the motion of an object that cause
it to have a world-line???
If that was your question, you should have asked it in the first place.
You asked: "how does an individual object have world-line?" The answer is
that motion really has nothing to do with it; an object has a world line
if it is somewhere at any given time.
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html
.
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| User: "kenseto" |
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| Title: Re: Questions on world-line |
24 Aug 2006 03:50:21 PM |
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"Timo A. Nieminen" <timo@physics.uq.edu.au> wrote in message
news:Pine.WNT.4.64.0608250424530.1512@serene.st...
On Wed, 23 Aug 2006, kenseto wrote:
"Timo A. Nieminen" <timo@physics.uq.edu.au> wrote:
On Tue, 22 Aug 2006, kenseto wrote:
In SR the world line is the path of an object in space with the
passage
of
time. Each object has its own world-line.
Questions:
1. Does this mean that the world-line of an object is the result of
the
individual motion of the object?
2. SR says that there is no such thing as individual motion. There is
only
relative motion then how does an individual object have world-line?
Consider an object, with position in a particular inertial coordinate
system (aka inertial reference frame) given by r(t). It can only be in
one
place at a time, and is always somewhere at any time; thus r(t) is a
function. The problem is that not only does r depend on choice of
coordinate system, but so does t.
So, what to do? Introduce a parameter that is independent of choice of
coordinate system, such as the "proper time" T, and we can write
R(T) = (r,t)
as a 4-vector valued function. How can any individual object _not_ have
a
world line?
[cut]
You did not answer my question: What is the motion of an object that
cause
it to have a world-line???
If that was your question, you should have asked it in the first place.
You asked: "how does an individual object have world-line?" The answer is
that motion really has nothing to do with it; an object has a world line
if it is somewhere at any given time.
An object somewhere at any given time and somewhere else at different given
time is velocity. So your bogus assertion is a bunch of baloney.
Ken Seto
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html
.
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| User: "Igor" |
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| Title: Re: Questions on world-line |
24 Aug 2006 03:58:35 PM |
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kenseto wrote:
"Timo A. Nieminen" <timo@physics.uq.edu.au> wrote in message
news:Pine.WNT.4.64.0608250424530.1512@serene.st...
On Wed, 23 Aug 2006, kenseto wrote:
"Timo A. Nieminen" <timo@physics.uq.edu.au> wrote:
On Tue, 22 Aug 2006, kenseto wrote:
In SR the world line is the path of an object in space with the
passage
of
time. Each object has its own world-line.
Questions:
1. Does this mean that the world-line of an object is the result of
the
individual motion of the object?
2. SR says that there is no such thing as individual motion. There is
only
relative motion then how does an individual object have world-line?
Consider an object, with position in a particular inertial coordinate
system (aka inertial reference frame) given by r(t). It can only be in
one
place at a time, and is always somewhere at any time; thus r(t) is a
function. The problem is that not only does r depend on choice of
coordinate system, but so does t.
So, what to do? Introduce a parameter that is independent of choice of
coordinate system, such as the "proper time" T, and we can write
R(T) = (r,t)
as a 4-vector valued function. How can any individual object _not_ have
a
world line?
[cut]
You did not answer my question: What is the motion of an object that
cause
it to have a world-line???
If that was your question, you should have asked it in the first place.
You asked: "how does an individual object have world-line?" The answer is
that motion really has nothing to do with it; an object has a world line
if it is somewhere at any given time.
An object somewhere at any given time and somewhere else at different given
time is velocity. So your bogus assertion is a bunch of baloney.
And if that's your definition of velocity, no wonder you're having
trouble understanding all this.
.
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| User: "kenseto" |
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| Title: Re: Questions on world-line |
25 Aug 2006 08:34:34 AM |
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"Igor" <thoovler@excite.com> wrote in message
news:1156453115.500831.55120@i3g2000cwc.googlegroups.com...
kenseto wrote:
"Timo A. Nieminen" <timo@physics.uq.edu.au> wrote in message
news:Pine.WNT.4.64.0608250424530.1512@serene.st...
On Wed, 23 Aug 2006, kenseto wrote:
"Timo A. Nieminen" <timo@physics.uq.edu.au> wrote:
On Tue, 22 Aug 2006, kenseto wrote:
In SR the world line is the path of an object in space with the
passage
of
time. Each object has its own world-line.
Questions:
1. Does this mean that the world-line of an object is the result
of
the
individual motion of the object?
2. SR says that there is no such thing as individual motion. There
is
only
relative motion then how does an individual object have
world-line?
Consider an object, with position in a particular inertial
coordinate
system (aka inertial reference frame) given by r(t). It can only be
in
one
place at a time, and is always somewhere at any time; thus r(t) is
a
function. The problem is that not only does r depend on choice of
coordinate system, but so does t.
So, what to do? Introduce a parameter that is independent of choice
of
coordinate system, such as the "proper time" T, and we can write
R(T) = (r,t)
as a 4-vector valued function. How can any individual object _not_
have
a
world line?
[cut]
You did not answer my question: What is the motion of an object that
cause
it to have a world-line???
If that was your question, you should have asked it in the first
place.
You asked: "how does an individual object have world-line?" The answer
is
that motion really has nothing to do with it; an object has a world
line
if it is somewhere at any given time.
An object somewhere at any given time and somewhere else at different
given
time is velocity. So your bogus assertion is a bunch of baloney.
And if that's your definition of velocity, no wonder you're having
trouble understanding all this.
That's my definition of motion. If an object is at different location at
different time then he is in a state of motion.
.
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| User: "Barry" |
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| Title: Re: Questions on world-line |
24 Aug 2006 04:46:38 PM |
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Timo A. Nieminen wrote:
On Wed, 23 Aug 2006, kenseto wrote:
You did not answer my question: What is the motion of an object that
cause
it to have a world-line???
The answer
is that motion really has nothing to do with it; an object has a world
line if it is somewhere at any given time.
I don't think so.
An object has a world line if it is somewhere or somewheres throughout a
period of time.
Motion does have something to do with it, the object must move through
spacetime. What you describe might be more accurately called an event
(or a cotemperaneous cluster of events).
Barry
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| User: "Ahmed Ouahi, Architect" |
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| Title: Re: Questions on world-line |
22 Aug 2006 03:47:58 PM |
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The flecked river
Which kept flowing and never
The same way twice flowing
Through many places
As if it stood still in one
-- Wallace Stevens
--
Ahmed Ouahi, Architect
Best Regards!
"kenseto" <kenseto@erinet.com> wrote in message
news:JdFGg.64268$vl5.40512@tornado.ohiordc.rr.com...
In SR the world line is the path of an object in space with the passage of
time. Each object has its own world-line.
Questions:
1. Does this mean that the world-line of an object is the result of the
individual motion of the object?
2. SR says that there is no such thing as individual motion. There is only
relative motion then how does an individual object have world-line?
Ken Seto
.
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| User: "Igor" |
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| Title: Re: Questions on world-line |
22 Aug 2006 11:53:02 AM |
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kenseto wrote:
In SR the world line is the path of an object in space with the passage of
time.
Not quite. It's literally the path taken through spacetime.
Each object has its own world-line.
Yes.
Questions:
1. Does this mean that the world-line of an object is the result of the
individual motion of the object?
Yes, through spacetime, but as opposed to what?
2. SR says that there is no such thing as individual motion.
Depends on what you mean by individual motion. If you mean absolute,
then you're correct.
There is only
relative motion then how does an individual object have world-line?
The world line is fixed in spacetime. It's invariant, so everyone
agrees on the path. How you define the coordinate system, however, is
entirely up to you. That's where relative motion comes in.
.
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| User: "kenseto" |
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| Title: Re: Questions on world-line |
22 Aug 2006 02:57:25 PM |
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"Igor" <thoovler@excite.com> wrote in message
news:1156265582.026355.324580@p79g2000cwp.googlegroups.com...
kenseto wrote:
In SR the world line is the path of an object in space with the passage
of
time.
Not quite. It's literally the path taken through spacetime.
Each object has its own world-line.
Yes.
Questions:
1. Does this mean that the world-line of an object is the result of the
individual motion of the object?
Yes, through spacetime, but as opposed to what?
2. SR says that there is no such thing as individual motion.
Depends on what you mean by individual motion. If you mean absolute,
then you're correct.
There is only
relative motion then how does an individual object have world-line?
The world line is fixed in spacetime. It's invariant, so everyone
agrees on the path. How you define the coordinate system, however, is
entirely up to you. That's where relative motion comes in.
The question is: how does an object have world line? What make it trace out
a world line?
.
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| User: "Igor" |
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| Title: Re: Questions on world-line |
23 Aug 2006 11:17:12 AM |
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kenseto wrote:
"Igor" <thoovler@excite.com> wrote in message
news:1156265582.026355.324580@p79g2000cwp.googlegroups.com...
kenseto wrote:
In SR the world line is the path of an object in space with the passage
of
time.
Not quite. It's literally the path taken through spacetime.
Each object has its own world-line.
Yes.
Questions:
1. Does this mean that the world-line of an object is the result of the
individual motion of the object?
Yes, through spacetime, but as opposed to what?
2. SR says that there is no such thing as individual motion.
Depends on what you mean by individual motion. If you mean absolute,
then you're correct.
There is only
relative motion then how does an individual object have world-line?
The world line is fixed in spacetime. It's invariant, so everyone
agrees on the path. How you define the coordinate system, however, is
entirely up to you. That's where relative motion comes in.
The question is: how does an object have world line? What make it trace out
a world line?
The best analogy would be a trajectory in spacetime. What makes a body
have a trajectory? In classical physics, all bodies have a unique
trajectory, as opposed to QM, where their trajectories become smeared
over many different paths.
.
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| User: "kenseto" |
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| Title: Re: Questions on world-line |
23 Aug 2006 11:30:54 AM |
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"Igor" <thoovler@excite.com> wrote in message
news:1156349832.759078.175940@74g2000cwt.googlegroups.com...
kenseto wrote:
"Igor" <thoovler@excite.com> wrote in message
news:1156265582.026355.324580@p79g2000cwp.googlegroups.com...
kenseto wrote:
In SR the world line is the path of an object in space with the
passage
of
time.
Not quite. It's literally the path taken through spacetime.
Each object has its own world-line.
Yes.
Questions:
1. Does this mean that the world-line of an object is the result of
the
individual motion of the object?
Yes, through spacetime, but as opposed to what?
2. SR says that there is no such thing as individual motion.
Depends on what you mean by individual motion. If you mean absolute,
then you're correct.
There is only
relative motion then how does an individual object have world-line?
The world line is fixed in spacetime. It's invariant, so everyone
agrees on the path. How you define the coordinate system, however, is
entirely up to you. That's where relative motion comes in.
The question is: how does an object have world line? What make it trace
out
a world line?
The best analogy would be a trajectory in spacetime. What makes a body
have a trajectory? In classical physics, all bodies have a unique
trajectory, as opposed to QM, where their trajectories become smeared
over many different paths.
The point is: worldline or trajectory in spacetime requires some kind of
motion to happen. In SR there is only relative motion.....does that mean
that worldline of an object is the result of relative motion??
.
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| User: "Ahmed Ouahi, Architect" |
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| Title: Re: Questions on world-line |
23 Aug 2006 12:43:31 PM |
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However, a certainly, as for instance, when anyone would be tracing the
surface of the earth as it would look from a high a distance out in a space.
Therefore, the line always goes up and down, a systematically along an
infinite amount of a trees as along an infinite amount of a buildings.
However, otherwise, at first the surface would get a smoother, as the
roundness of anything as of the hoods passes a definitely out of a view,
when especially, it would be seen along anything or along any mechanical
zooming, which it would be an apparently along a random way, a definitely as
a matter a fact.
--
Ahmed Ouahi, Architect
Best Regards!
"kenseto" <kenseto@erinet.com> wrote in message
news:2p%Gg.68962$u11.35108@tornado.ohiordc.rr.com...
"Igor" <thoovler@excite.com> wrote in message
news:1156349832.759078.175940@74g2000cwt.googlegroups.com...
kenseto wrote:
"Igor" <thoovler@excite.com> wrote in message
news:1156265582.026355.324580@p79g2000cwp.googlegroups.com...
kenseto wrote:
In SR the world line is the path of an object in space with the
passage
of
time.
Not quite. It's literally the path taken through spacetime.
Each object has its own world-line.
Yes.
Questions:
1. Does this mean that the world-line of an object is the result
of
the
individual motion of the object?
Yes, through spacetime, but as opposed to what?
2. SR says that there is no such thing as individual motion.
Depends on what you mean by individual motion. If you mean
absolute,
then you're correct.
There is only
relative motion then how does an individual object have
world-line?
The world line is fixed in spacetime. It's invariant, so everyone
agrees on the path. How you define the coordinate system, however,
is
entirely up to you. That's where relative motion comes in.
The question is: how does an object have world line? What make it
trace
out
a world line?
The best analogy would be a trajectory in spacetime. What makes a body
have a trajectory? In classical physics, all bodies have a unique
trajectory, as opposed to QM, where their trajectories become smeared
over many different paths.
The point is: worldline or trajectory in spacetime requires some kind of
motion to happen. In SR there is only relative motion.....does that mean
that worldline of an object is the result of relative motion??
.
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| User: "YBM" |
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| Title: Re: Questions on world-line |
23 Aug 2006 12:07:34 PM |
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kenseto a écrit :
The point is: worldline or trajectory in spacetime requires some kind of
motion to happen. In SR there is only relative motion.....does that mean
that worldline of an object is the result of relative motion??
I should be dreaming... You are just about to get it !
.
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| User: "kenseto" |
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| Title: Re: Questions on world-line |
23 Aug 2006 02:44:26 PM |
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"YBM" <ybmess@nooos.fr> wrote in message
news:44ec8a99$0$19782$636a55ce@news.free.fr...
kenseto a écrit :
The point is: worldline or trajectory in spacetime requires some kind of
motion to happen. In SR there is only relative motion.....does that mean
that worldline of an object is the result of relative motion??
I should be dreaming... You are just about to get it !
RFOTFLOL this idiot falls into the trap.....an object doesn't need any
reference to have a worldline.
.
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| User: "YBM" |
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| Title: Re: Questions on world-line |
23 Aug 2006 06:31:07 PM |
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kenseto a écrit :
"YBM" <ybmess@nooos.fr> wrote in message
news:44ec8a99$0$19782$636a55ce@news.free.fr...
kenseto a écrit :
The point is: worldline or trajectory in spacetime requires some kind of
motion to happen. In SR there is only relative motion.....does that mean
that worldline of an object is the result of relative motion??
I should be dreaming... You are just about to get it !
RFOTFLOL this idiot falls into the trap.....an object doesn't need any
reference to have a worldline.
Well, I'm right not to have bet on that... not that I did believe it
actualy.
Back to basics : the worldline of Ken Seto is defined in a specific
frame F as the set of the t-uples (x,y,z,t) tagging in F the events
"at time t, Ken Seto is at coordinates (x,y,z)".
Is their anything else than your relative motion (or rest) wrt F
which completely define this set called "worldline" ?
[ ] No
[ ] Yes. Please fill here : ______________________________
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| User: "kenseto" |
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| Title: Re: Questions on world-line |
24 Aug 2006 08:17:46 AM |
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"YBM" <ybmess@nooos.fr> wrote in message
news:44ece480$0$19781$636a55ce@news.free.fr...
kenseto a écrit :
"YBM" <ybmess@nooos.fr> wrote in message
news:44ec8a99$0$19782$636a55ce@news.free.fr...
kenseto a écrit :
The point is: worldline or trajectory in spacetime requires some kind
of
motion to happen. In SR there is only relative motion.....does that
mean
that worldline of an object is the result of relative motion??
I should be dreaming... You are just about to get it !
RFOTFLOL this idiot falls into the trap.....an object doesn't need any
reference to have a worldline.
Well, I'm right not to have bet on that... not that I did believe it
actualy.
Back to basics : the worldline of Ken Seto is defined in a specific
frame F as the set of the t-uples (x,y,z,t) tagging in F the events
"at time t, Ken Seto is at coordinates (x,y,z)".
This is not basic you are talking about relative motion between me and
frame F. In my frame of reference my coordinates are (0,0,0) at all time.
Why? Because SR and I assumed that I am in a state of rest and all the
objects around me are doing the moving. Even though that I assume that I am
in a state of rest I still have a worldline. This applies to all the object
that are at rest wrt me.
Ken Seto
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| User: "Ahmed Ouahi, Architect" |
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| Title: Re: Questions on world-line |
24 Aug 2006 09:42:59 AM |
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However, when you do give a complicated image along anything you would like
to attain, therefore, the behaviours along that matter would be always more
complicated.
Whether, the things which are already known, is that, any object along the
universe has its own a motion, not only always a relative but most of the
time also a depending .
However, on the fact of its structure and its structuration and a definitely
on the mass as on any excessivity of any force all along, especially of the
object itself, whether could be an infinitesimal objet what is all about.
--
Ahmed Ouahi, Architect
Best Regards!
"kenseto" <kenseto@erinet.com> wrote in message
news:_FhHg.69400$vl5.11915@tornado.ohiordc.rr.com...
"YBM" <ybmess@nooos.fr> wrote in message
news:44ece480$0$19781$636a55ce@news.free.fr...
kenseto a écrit :
"YBM" <ybmess@nooos.fr> wrote in message
news:44ec8a99$0$19782$636a55ce@news.free.fr...
kenseto a écrit :
The point is: worldline or trajectory in spacetime requires some kind
of
motion to happen. In SR there is only relative motion.....does that
mean
that worldline of an object is the result of relative motion??
I should be dreaming... You are just about to get it !
RFOTFLOL this idiot falls into the trap.....an object doesn't need any
reference to have a worldline.
Well, I'm right not to have bet on that... not that I did believe it
actualy.
Back to basics : the worldline of Ken Seto is defined in a specific
frame F as the set of the t-uples (x,y,z,t) tagging in F the events
"at time t, Ken Seto is at coordinates (x,y,z)".
This is not basic you are talking about relative motion between me and
frame F. In my frame of reference my coordinates are (0,0,0) at all time.
Why? Because SR and I assumed that I am in a state of rest and all the
objects around me are doing the moving. Even though that I assume that I
am
in a state of rest I still have a worldline. This applies to all the
object
that are at rest wrt me.
Ken Seto
.
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| User: "YBM" |
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| Title: Re: Questions on world-line |
24 Aug 2006 12:08:17 PM |
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kenseto a écrit :
"YBM" <ybmess@nooos.fr> wrote in message
news:44ece480$0$19781$636a55ce@news.free.fr...
kenseto a écrit :
"YBM" <ybmess@nooos.fr> wrote in message
news:44ec8a99$0$19782$636a55ce@news.free.fr...
kenseto a écrit :
The point is: worldline or trajectory in spacetime requires some kind
of
motion to happen. In SR there is only relative motion.....does that
mean
that worldline of an object is the result of relative motion??
I should be dreaming... You are just about to get it !
RFOTFLOL this idiot falls into the trap.....an object doesn't need any
reference to have a worldline.
Well, I'm right not to have bet on that... not that I did believe it
actualy.
Back to basics : the worldline of Ken Seto is defined in a specific
frame F as the set of the t-uples (x,y,z,t) tagging in F the events
"at time t, Ken Seto is at coordinates (x,y,z)".
This is not basic you are talking about relative motion between me and
frame F. In my frame of reference my coordinates are (0,0,0) at all time.
Why? Because SR and I assumed that I am in a state of rest and all the
objects around me are doing the moving. Even though that I assume that I am
in a state of rest I still have a worldline. This applies to all the object
that are at rest wrt me.
So what ? In that case (Seto at rest in F), my definition works as well
and gives { (x_s,y_s,z_s,t) / t \in R } where (x_s,y_s,z_s) is your
constant spacial coordinates...
BTW, you seem (in another post of this thread) to suggest that a
worldline could be defined without refering to a frame. Please do so.
.
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| User: "kenseto" |
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| Title: Re: Questions on world-line |
25 Aug 2006 08:46:37 AM |
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"YBM" <ybmess@nooos.fr> wrote in message
news:44eddc45$0$19777$636a55ce@news.free.fr...
kenseto a écrit :
"YBM" <ybmess@nooos.fr> wrote in message
news:44ece480$0$19781$636a55ce@news.free.fr...
kenseto a écrit :
"YBM" <ybmess@nooos.fr> wrote in message
news:44ec8a99$0$19782$636a55ce@news.free.fr...
kenseto a écrit :
The point is: worldline or trajectory in spacetime requires some kind
of
motion to happen. In SR there is only relative motion.....does that
mean
that worldline of an object is the result of relative motion??
I should be dreaming... You are just about to get it !
RFOTFLOL this idiot falls into the trap.....an object doesn't need any
reference to have a worldline.
Well, I'm right not to have bet on that... not that I did believe it
actualy.
Back to basics : the worldline of Ken Seto is defined in a specific
frame F as the set of the t-uples (x,y,z,t) tagging in F the events
"at time t, Ken Seto is at coordinates (x,y,z)".
This is not basic you are talking about relative motion between me
and
frame F. In my frame of reference my coordinates are (0,0,0) at all
time.
Why? Because SR and I assumed that I am in a state of rest and all the
objects around me are doing the moving. Even though that I assume that I
am
in a state of rest I still have a worldline. This applies to all the
object
that are at rest wrt me.
So what ? In that case (Seto at rest in F), my definition works as well
and gives { (x_s,y_s,z_s,t) / t \in R } where (x_s,y_s,z_s) is your
constant spacial coordinates...
You keep on using F as a reference for me. I can have a world line without
any reference. F can see that I have a different world line after I
accelerated. But that's because I changed my state of absolute motion.
BTW, you seem (in another post of this thread) to suggest that a
worldline could be defined without refering to a frame. Please do so.
.
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| User: "YBM" |
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| Title: Re: Questions on world-line |
25 Aug 2006 10:41:02 AM |
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kenseto a écrit :
"YBM" <ybmess@nooos.fr> wrote in message
....
So what ? In that case (Seto at rest in F), my definition works as well
and gives { (x_s,y_s,z_s,t) / t \in R } where (x_s,y_s,z_s) is your
constant spacial coordinates...
You keep on using F as a reference for me. I can have a world line without
any reference. F can see that I have a different world line after I
accelerated. But that's because I changed my state of absolute motion.
Please define what a world line is without reference to a given frame.
BTW, you seem (in another post of this thread) to suggest that a
worldline could be defined without refering to a frame. Please do so.
.
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| User: "kenseto" |
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| Title: Re: Questions on world-line |
25 Aug 2006 06:16:22 PM |
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"YBM" <ybmess@nooos.fr> wrote in message
news:44ef194f$0$19795$636a55ce@news.free.fr...
kenseto a écrit :
"YBM" <ybmess@nooos.fr> wrote in message
...
So what ? In that case (Seto at rest in F), my definition works as well
and gives { (x_s,y_s,z_s,t) / t \in R } where (x_s,y_s,z_s) is your
constant spacial coordinates...
You keep on using F as a reference for me. I can have a world line
without
any reference. F can see that I have a different world line after I
accelerated. But that's because I changed my state of absolute motion.
Please define what a world line is without reference to a given frame.
World line is a path of an object in space traces out by its absolute
motion. Relative motion between two objects A and B is the vector difference
of the vector components of A's absolute motion and the vector component of
B's absolute motion along the line joining A and B.
Ken Seto
BTW, you seem (in another post of this thread) to suggest that a
worldline could be defined without refering to a frame. Please do so.
.
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| User: "YBM" |
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| Title: Re: Questions on world-line |
25 Aug 2006 08:48:14 PM |
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kenseto a écrit :
World line is a path of an object in space traces out by its absolute
motion.
Whis this definition, which assumes absolute motion, it is indeed clear
that worldline => absolute motion.
Note that it is NOT the definition of worldline for the rest of us.
Relative motion between two objects A and B is the vector difference
of the vector components of A's absolute motion and the vector component of
B's absolute motion along the line joining A and B.
For the rest of us relative motion does NOT need to refer to absolute
motion to be defined. Could you provide at least one case where your
definition of relative motion will give another result than the usual
one ?
.
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| User: "kenseto" |
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| Title: Re: Questions on world-line |
26 Aug 2006 08:05:50 AM |
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"YBM" <ybmess@nooos.fr> wrote in message
news:44efa79f$0$19782$636a55ce@news.free.fr...
kenseto a écrit :
World line is a path of an object in space traces out by its absolute
motion.
Whis this definition, which assumes absolute motion, it is indeed clear
that worldline => absolute motion.
Note that it is NOT the definition of worldline for the rest of us.
SO???? It just mean that the rest of you are wrong. :-)
Relative motion between two objects A and B is the vector difference
of the vector components of A's absolute motion and the vector component
of
B's absolute motion along the line joining A and B.
For the rest of us relative motion does NOT need to refer to absolute
motion to be defined. Could you provide at least one case where your
definition of relative motion will give another result than the usual
one ?
You and I are standing side by side. That means that you and I are in the
same state of absolute motion. I accelerated away from you and maintain a
constant relative velocity wrt you. My acceleration causes me to have a
different state of absolute motion than you and thus a different world line
than you. This clearly show that the relative velocity between us is derived
from my individual motion.
Ken Seto
.
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| User: "YBM" |
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| Title: Re: Questions on world-line |
26 Aug 2006 08:19:55 AM |
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kenseto a écrit :
"YBM" <ybmess@nooos.fr> wrote in message
news:44efa79f$0$19782$636a55ce@news.free.fr...
kenseto a écrit :
World line is a path of an object in space traces out by its absolute
motion.
Whis this definition, which assumes absolute motion, it is indeed clear
that worldline => absolute motion.
Note that it is NOT the definition of worldline for the rest of us.
SO???? It just mean that the rest of you are wrong. :-)
Relative motion between two objects A and B is the vector difference
of the vector components of A's absolute motion and the vector component
of
B's absolute motion along the line joining A and B.
For the rest of us relative motion does NOT need to refer to absolute
motion to be defined. Could you provide at least one case where your
definition of relative motion will give another result than the usual
one ?
You and I are standing side by side. That means that you and I are in the
same state of absolute motion. I accelerated away from you and maintain a
constant relative velocity wrt you. My acceleration causes me to have a
different state of absolute motion than you and thus a different world line
than you. This clearly show that the relative velocity between us is derived
from my individual motion.
You and I are standing side by side. That means that you and I have a
relative velocity of 0. You accelerated away from me, then you change
your relative velocity wrt me. Your acceleration causes you to have a
different relative velocity wrt me than you had before.
.
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| User: "kenseto" |
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| Title: Re: Questions on world-line |
27 Aug 2006 07:20:44 AM |
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"YBM" <ybmess@nooos.fr> wrote in message
news:44f049bc$0$19777$636a55ce@news.free.fr...
kenseto a écrit :
"YBM" <ybmess@nooos.fr> wrote in message
news:44efa79f$0$19782$636a55ce@news.free.fr...
kenseto a écrit :
World line is a path of an object in space traces out by its absolute
motion.
Whis this definition, which assumes absolute motion, it is indeed clear
that worldline => absolute motion.
Note that it is NOT the definition of worldline for the rest of us.
SO???? It just mean that the rest of you are wrong. :-)
Relative motion between two objects A and B is the vector difference
of the vector components of A's absolute motion and the vector
component
of
B's absolute motion along the line joining A and B.
For the rest of us relative motion does NOT need to refer to absolute
motion to be defined. Could you provide at least one case where your
definition of relative motion will give another result than the usual
one ?
You and I are standing side by side. That means that you and I are in
the
same state of absolute motion. I accelerated away from you and maintain
a
constant relative velocity wrt you. My acceleration causes me to have a
different state of absolute motion than you and thus a different world
line
than you. This clearly show that the relative velocity between us is
derived
from my individual motion.
You and I are standing side by side. That means that you and I have a
relative velocity of 0. You accelerated away from me, then you change
your relative velocity wrt me. Your acceleration causes you to have a
different relative velocity wrt me than you had before.
Hey idiot.....I don't need you as a reference to know that I experienced a
change in my state of motion due to my acceleration. It appears that you
don't know what acceleration means.
.
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| User: "YBM" |
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| Title: Re: Questions on world-line |
27 Aug 2006 12:08:43 PM |
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kenseto wrote :
"YBM" <ybmess@nooos.fr> wrote in message
news:44f049bc$0$19777$636a55ce@news.free.fr...
....
You and I are standing side by side. That means that you and I have a
relative velocity of 0. You accelerated away from me, then you change
your relative velocity wrt me. Your acceleration causes you to have a
different relative velocity wrt me than you had before.
Hey idiot.....I don't need you as a reference to know that I experienced a
change in my state of motion due to my acceleration.
Got it, you're dense.
.
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| User: "Igor" |
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| Title: Re: Questions on world-line |
26 Aug 2006 12:58:54 PM |
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kenseto wrote:
"YBM" <ybmess@nooos.fr> wrote in message
news:44efa79f$0$19782$636a55ce@news.free.fr...
kenseto a =E9crit :
World line is a path of an object in space traces out by its absolute
motion.
Whis this definition, which assumes absolute motion, it is indeed clear
that worldline =3D> absolute motion.
Note that it is NOT the definition of worldline for the rest of us.
SO???? It just mean that the rest of you are wrong. :-)
That's funny, but there are people in mental institutions all over the
world that basically keep saying the same thing.
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